There is an
\href{http://www.wilbaden.com/neil_bawd/easter.txt}{Easter date calculator}
\index{easter} \index{computus@\textit{computus}}

\begin{framed}
\begin{Verbatim}
    new
    #include ../demos/easter.fs
\end{Verbatim}
\end{framed}
    
Now you can do

\begin{framed}
\begin{Verbatim}
    >2015 .easter
    2015 April 5   ok
\end{Verbatim}
\end{framed}

Or even

\begin{framed}
\begin{Verbatim}
    >: 20easters
    +  2035 2015 do
    +    cr i .easter
    +  loop
    +;
     ok
    >20easters

    2015 April 5 
    2016 March 27 
    2017 April 16 
    2018 April 1 
    2019 April 21 
    2020 April 12 
    2021 April 4 
    2022 April 17 
    2023 April 9 
    2024 March 31 
    2025 April 20 
    2026 April 5 
    2027 March 28 
    2028 April 16 
    2029 April 1 
    2030 April 21 
    2031 April 13 
    2032 March 28 
    2033 April 17 
    2034 April 9   ok
\end{Verbatim}
\end{framed}
